If you want to copy you files to another ArcGIS Online account, use the free tool "ArcGIS Online Assistant":
To use the tool to copy your contents from Carleton's ArcGIS Online to another ArcGIS Online account, first log in your Carleton's ArcGIS Online account, select the task you want to perform (Copy Content), Select "Another Account" and follow prompts to log in your other ArcGIS Online account, and perform the copy following prompts.
This tool DOES NOT copy pictures if the pictures are saved with Web maps or apps, as opposed to uploaded as an item (if you don't see the picture in your content list, it is not uploaded as an item). To retrieve pictures saved with Web maps and apps, find the URLs' for the pictures and download the pictures. The pictures will be deleted with the Web maps and apps when your files are deleted. If you need help using ArcGIS Online Assistant or retrieve your pictures, please contact the support person at your new organization or Wei-Hsin Fu at Carleton College, firstname.lastname@example.org)